<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            width: 200px;
            height: 200px;
            margin: 0 auto;
            text-align: center;
            line-height: 100px;
        }
        .box1{
            background-color: violet;
            border-radius: 100% 100px 100% 100px;
        }
        .box2{
            background-color: skyblue;
            border-radius: 100% 100% 100% 100%;
        }
        .box3{
            background-color: khaki;
            border-radius: 0 100px 100% 100px;
        }
    </style>
</head>
<body>
    <div class="box1">
        border-radius: 100% 100px 100% 100px;
    </div>
    <div class="box2">
        border-radius: 100% 100px 100% 100px;
    </div>
    <div class="box3">
        border-radius: 0 100px 100% 100px;
    </div>
</body>
</html>